The present invention relates to the field of electronic design automation for integrated circuit, and in particular, to filling vacant areas of a routed design with metal attached to power or ground.
Integrated circuits are important building blocks of the information age and are critical to the information age, affecting every industry including financial, banking, legal, military, high technology, transportation, telephony, oil, medical, drug, food, agriculture, education, and many others. Integrated circuits such as DSPs, amplifiers, DRAMs, SRAMs, EPROMs, EEPROMs, Flash memories, microprocessors, ASICs, and programmable logic are used in many applications such as computers, networking, telecommunications, and consumer electronics.
Consumers continue to demand greater performance in their electronic products. For example, higher speed computers will provide higher speed graphics for multimedia applications or development. Higher speed internet web servers will lead to greater on-line commerce including on-line stock trading, book sales, auctions, and grocery shopping, just to name a few examples. Higher performance integrated circuits will improve the performance of the products in which they are incorporated.
Large modern day integrated circuits have millions of devices including gates and transistors and are very complex. As process technology improves, more and more devices may be fabricated on a single integrated circuit, so integrated circuits will continue to become even more complex with time. To meet the challenges of building more complex and higher performance integrated circuits, software tools are used. These tools are in an area commonly referred to as computer aided design (CAD), computer aided engineering (CAE), or electronic design automation (EDA). There is a constant need to improve these electronic automatic tools in order to address the desire to for higher integration and better performance in integrated circuits.
An integrated circuit may be specified using a netlist and a layout. The netlist provides information about devices or components of the integrated circuit and their connectivity. The integrated circuit layout or integrated circuit mask layout is the representation of an integrated circuit in terms of planar geometric shapes, patterns, and features that correspond to shapes used in a mask to fabricate the circuit. A design engineer or mask designer may create the layout the integrated circuit. Some features in the layout or certain masks may be automatically generated, such as automatically routed.
In a typical layout, there are a very large number of shapes, patterns, and features. It may be desirable (or required) to fill vacant areas of a routed design with metal (or any other material) attached to power and ground (or other desirable connection). This process is often carried out by layout engineers manually drawing shapes in unused areas, while trying to conform to the layout design (or DRC) rules. As can be appreciated, this manual process is very time consuming
Therefore, there is a need for improved technique for filling vacant areas of integrated circuit design, especially where these vacant areas are filled with metal or another conductor connected to a supply line such as power or ground.